Throughout history, the ancestral diet has evolved to give rise to the current westernized pattern. This is characterized by a high presence of animal fats and proteins, sugars and processed foods, together with a decrease in the consumption of fresh foods, both fruits and vegetables and fish.
The data is worrying because diets high in sugar, animal products, red meat and alcohol have been linked to the development of colorectal cancer. Quite the opposite of whole grains, fruits and vegetables, which have shown a protective effect against this pathology.
Embers, smoke and roasting
Regardless of nutritional characteristics, modern diets have a high presence of processed foods. These are usually rich in additives that prolong their useful life and improve their organoleptic properties. To top it off, when preparing them, on many occasions we choose quick and simple culinary techniques such as grilling, barbecue, grilling or frying, which result in golden, crunchy and tasty foods.
It is within this context that the term xenobiotic. Under this name are included all the external substances to the organism that we add to the food during its processing or cooking. Most of them are generated during high-temperature cooking and have the ability to damage our cells, increasing the risk of injury and tumor progression.
There are different types of xenobiotic compounds. Among the most important are heterocyclic amines and polycyclic aromatic hydrocarbons. They are not naturally present in food, but we incorporate them mainly when we cook meat and fish at high temperatures.
They are also formed during the incomplete combustion of wood or coal and are deposited on top of the product, giving rise to that smoky flavor that different populations like so much. Hence, they are present in smoked products.
Then there are nitrites and nitrates, naturally present in some foods such as vegetables, which are also often used as food additives to preserve meats, cheeses, etc. And acrylamide, which is generated in foods rich in baked, toasted or fried carbohydrates. For example, French fries or toast for breakfast.
Better grilled than on the barbecue
Depending on the xenobiotic compound, the recommendation of some culinary techniques over others could be considered. For example, 100 grams of a chicken thigh with barbecue skin leads to the formation of 17,950 ng of a compound called PhlP, a heterocyclic amine classified as a possible carcinogen, according to the IARC (International Agency for Research on Cancer). However, the same portion cooked on the grill accounts for less than a quarter of this compound. And if we prepare it in the oven, it is drastically reduced.
Therefore, it is not only what we eat that matters but how we cook it. In general, it is advisable to avoid direct contact of the food with the heat source, reducing the brown color of the surface. As an alternative, you can use techniques in which you cook for a longer time but at low temperatures. At temperatures below 150 ℃, virtually undetectable levels of these compounds appear.
Culinary techniques such as marinating meat or fish, marinating, the use of spices, garlic or lemon, and the use of olive oil have been shown to reduce the formation of these compounds.
In the case of the barbecue, the use of vertical barbecues could reduce the formation of xenobiotics between 10 and 30 times. Probably because it prevents meat and fish from absorbing the smoke produced by burning fat on the charcoal. Using additives to achieve the smoky flavor is another healthier alternative.
On the other hand, the formation of nitrosamines can be minimized using reducers such as vitamin C, vitamin E and polyphenols, naturally present in fruits, vegetables and vegetable oils.
It is also recommended to avoid over-baking of pastry products, as well as not to exceed 175℃ during frying in order to get yellowish-golden color instead of brownish-golden to decrease the amount of acrylamide in a food.
Xenobiotics, probiotics and microbiota
As for almost everything in food, the dose makes the poison. But what dose of xenobiotics is harmful? The answer is complicated.
When evaluating the impact of these compounds on health, it must be taken into account that an individual’s diet is very complex. The balance between substances with possible harmful action against our cells and beneficial substances can determine the progression of the damage. On the other hand, some dietary components such as fiber can counteract the damage of xenobiotics at the intestinal level.
For example, probiotics, which we can define as live microorganisms that, ingested in adequate amounts, have beneficial effects on health beyond those inherent in basic nutrition. Foods that contain probiotics, as well as fermented foods (with beneficial bacteria, fungi, and yeasts), can counteract the detrimental effect of xenobiotics. Hence, it is recommended to consume dairy and vegetable products such as yogurt, cheese, kefir, kombucha or sauerkraut.
Nor should we forget that the millions of microbes that we have in our intestines, known as intestinal microbiota, can modify the ability of xenobiotics to cause damage. That is why it is important to promote a correct composition of our microbiota through diet and healthy lifestyle habits.